Express 文档（数据库集成）

摘要：数据库集成添加将数据库连接到应用程序的功能只需在应用程序中为数据库加载适当的驱动程序，本文档简要介绍了如何在应用程序中为数据库系统添加和使用一些最流行的模块。这些数据库驱动程序是众多可用的驱动程序，对于其他选项，请在网站上搜索。

添加将数据库连接到Express应用程序的功能只需在应用程序中为数据库加载适当的Node.js驱动程序，本文档简要介绍了如何在Express应用程序中为数据库系统添加和使用一些最流行的Node.js模块。

这些数据库驱动程序是众多可用的驱动程序，对于其他选项，请在npm网站上搜索。

模块：cassandra-driver

$ npm install cassandra-driver

var cassandra = require("cassandra-driver")
var client = new cassandra.Client({ contactPoints: ["localhost"] })

client.execute("select key from system.local", function (err, result) {
  if (err) throw err
  console.log(result.rows[0])
})

模块：couchnode

$ npm install couchbase

var couchbase = require("couchbase")
var bucket = (new couchbase.Cluster("http://localhost:8091")).openBucket("bucketName")

// add a document to a bucket
bucket.insert("document-key", { name: "Matt", shoeSize: 13 }, function (err, result) {
  if (err) {
    console.log(err)
  } else {
    console.log(result)
  }
})

// get all documents with shoe size 13
var n1ql = "SELECT d.* FROM `bucketName` d WHERE shoeSize = $1"
var query = N1qlQuery.fromString(n1ql)
bucket.query(query, [13], function (err, result) {
  if (err) {
    console.log(err)
  } else {
    console.log(result)
  }
})

模块：nano

$ npm install nano

var nano = require("nano")("http://localhost:5984")
nano.db.create("books")
var books = nano.db.use("books")

// Insert a book document in the books database
books.insert({ name: "The Art of war" }, null, function (err, body) {
  if (err) {
    console.log(err)
  } else {
    console.log(body)
  }
})

// Get a list of all books
books.list(function (err, body) {
  if (err) {
    console.log(err)
  } else {
    console.log(body.rows)
  }
})

模块：levelup

$ npm install level levelup leveldown

var levelup = require("levelup")
var db = levelup("./mydb")

db.put("name", "LevelUP", function (err) {
  if (err) return console.log("Ooops!", err)

  db.get("name", function (err, value) {
    if (err) return console.log("Ooops!", err)

    console.log("name=" + value)
  })
})

模块：mysql

$ npm install mysql

var mysql = require("mysql")
var connection = mysql.createConnection({
  host     : "localhost",
  user     : "dbuser",
  password : "s3kreee7",
  database : "my_db"
});

connection.connect()

connection.query("SELECT 1 + 1 AS solution", function (err, rows, fields) {
  if (err) throw err

  console.log("The solution is: ", rows[0].solution)
})

connection.end()

模块：mongodb

$ npm install mongodb

var MongoClient = require("mongodb").MongoClient

MongoClient.connect("mongodb://localhost:27017/animals", function (err, db) {
  if (err) throw err

  db.collection("mammals").find().toArray(function (err, result) {
    if (err) throw err

    console.log(result)
  })
})

var MongoClient = require("mongodb").MongoClient

MongoClient.connect("mongodb://localhost:27017/animals", function (err, client) {
  if (err) throw err

  var db = client.db("animals")
  
  db.collection("mammals").find().toArray(function (err, result) {
    if (err) throw err

    console.log(result)
  })
})

如果你想要MongoDB的对象模型驱动程序，请查看Mongoose。

模块：apoc

$ npm install apoc

var apoc = require("apoc")

apoc.query("match (n) return n").exec().then(
  function (response) {
    console.log(response)
  },
  function (fail) {
    console.log(fail)
  }
)

模块：oracledb

注意：请参阅安装前提条件。

$ npm install oracledb

const oracledb = require("oracledb");
const config = {
  user: "",                // Update me
  password: "",        // Update me
  connectString: "localhost:1521/orcl"   // Update me
};

async function getEmployee(empId) {
  let conn;

  try {
    conn = await oracledb.getConnection(config);

    const result = await conn.execute(
      "select * from employees where employee_id = :id",
      [empId]
    );

    console.log(result.rows[0]);
  } catch (err) {
    console.log("Ouch!", err);
  } finally {
    if (conn) { // conn assignment worked, need to close
       await conn.close();
    }
  }
}

getEmployee(101);

模块：pg-promise

$ npm install pg-promise

var pgp = require("pg-promise")(/*options*/)
var db = pgp("postgres://username:password@host:port/database")

db.one("SELECT $1 AS value", 123)
  .then(function (data) {
    console.log("DATA:", data.value)
  })
  .catch(function (error) {
    console.log("ERROR:", error)
  })

模块：redis

$ npm install redis

var redis = require("redis")
var client = redis.createClient()

client.on("error", function (err) {
  console.log("Error " + err)
})

client.set("string key", "string val", redis.print)
client.hset("hash key", "hashtest 1", "some value", redis.print)
client.hset(["hash key", "hashtest 2", "some other value"], redis.print)

client.hkeys("hash key", function (err, replies) {
  console.log(replies.length + " replies:")

  replies.forEach(function (reply, i) {
    console.log("    " + i + ": " + reply)
  })

  client.quit()
})

模块：tedious

$ npm install tedious

var Connection = require("tedious").Connection;
var Request = require("tedious").Request;

var config = {
  userName: "your_username", // update me
  password: "your_password", // update me
  server: "localhost"
}

var connection = new Connection(config);

connection.on("connect", function(err) {
  if (err) {
    console.log(err);
  } else {
    executeStatement();
  }
});

function executeStatement() {
  request = new Request("select 123, "hello world"", function(err, rowCount) {
    if (err) {
      console.log(err);
    } else {
      console.log(rowCount + " rows");
    }
    connection.close();
  });

  request.on("row", function(columns) {
    columns.forEach(function(column) {
      if (column.value === null) {
        console.log("NULL");
      } else {
        console.log(column.value);
      }
    });
  });

  connection.execSql(request);
}

模块：sqlite3

$ npm install sqlite3

var sqlite3 = require("sqlite3").verbose()
var db = new sqlite3.Database(":memory:")

db.serialize(function () {
  db.run("CREATE TABLE lorem (info TEXT)")
  var stmt = db.prepare("INSERT INTO lorem VALUES (?)")

  for (var i = 0; i < 10; i++) {
    stmt.run("Ipsum " + i)
  }

  stmt.finalize()

  db.each("SELECT rowid AS id, info FROM lorem", function (err, row) {
    console.log(row.id + ": " + row.info)
  })
})

db.close()

模块：elasticsearch

$ npm install elasticsearch

var elasticsearch = require("elasticsearch")
var client = elasticsearch.Client({
  host: "localhost:9200"
})

client.search({
  index: "books",
  type: "book",
  body: {
    query: {
      multi_match: {
        query: "express js",
        fields: ["title", "description"]
      }
    }
  }
}).then(function (response) {
  var hits = response.hits.hits
}, function (error) {
  console.trace(error.message)
})